Complexation of 2,6-helic[6]arene and its derivatives with 1,1′-dimethyl-4,4′-bipyridinium salts and protonated 4,4'-bipyridinium salts: an acid–base controllable complexation

• Jing Li,
• Qiang Shi,
• Ying Han and
• Chuan-Feng Chen

Beilstein J. Org. Chem. 2019, 15, 1795–1804, doi:10.3762/bjoc.15.173

• are also the epitome of complex-binding pockets of enzymes [3]. Macrocyclic arenes including calixarenes [4][5], resorcinarenes [6], cyclotriveratrylenes [7][8], pillararenes [9], biphen[n]arenes [10] and others [11][12] are all composed of hydroxy-substituted aromatic rings bridged by methylene or

• the signal for protons b completely disappeared due to the shielding effect of the aromatic rings in hosts H1 or H4. The signals for the protons 2, 3, and 4 of H1 and 2, 3, 4, and 13 of H4 all showed downfield shifts, which might be attributed to the deshielding effect of guest G1. Other helic[6]arene

• time scale as well. The signal for protons d of the 4,4'-bipyridinium ring showed an upfield shift and that for protons e completely disappeared possibly due to the shielding effect of the aromatic rings in H1 or H4. The proton signals of 2 and 3 of H1 and 3 of H4 all showed upfield shifts with

Synthesis of 9-O-arylated berberines via copper-catalyzed C_Ar–O coupling reactions

• Qiaoqiao Teng,
• Xinhui Zhu,
• Qianqian Guo,
• Weihua Jiang,
• Jiang Liu and
• Qi Meng

Beilstein J. Org. Chem. 2019, 15, 1575–1580, doi:10.3762/bjoc.15.161

• elaborate motifs such as heterocycles [10][11][12], glucose [13], nitric oxide [14], and the multidrug-resistance pump inhibitor 5-nitro-2-phenylindole (INF55) [15] have been covalently attached to BBR, further widening its pharmacological spectrum. Aromatic rings are another family of substituents having

Self-assembly behaviors of perylene- and naphthalene-crown macrocycle conjugates in aqueous medium

• Xin Shen,
• Bo Li,
• Tiezheng Pan,
• Jianfeng Wu,
• Yangxin Wang,
• Jie Shang,
• Yan Ge,
• Lin Jin and
• Zhenhui Qi

Beilstein J. Org. Chem. 2019, 15, 1203–1209, doi:10.3762/bjoc.15.117

• through hydrogen bonding and metal ion coordination in nonpolar solvents [66][67][68]. Compared with NDI, PDI has more aromatic rings to generate stronger intermolecular π−π stacking, leading to molecular aggregates more easily, and these aggregates or supramolecular assemblies can give rise to desirable

Halogen bonding and host–guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests

• Fangfang Pan,
• Mohadeseh Dashti,
• Michael R. Reynolds,
• Kari Rissanen,
• John F. Trant and
• Ngong Kodiah Beyeh

Beilstein J. Org. Chem. 2019, 15, 947–954, doi:10.3762/bjoc.15.91

• anisotropy influence from the host’s aromatic rings, increasing the shielding. Conclusion In conclusion, we present XB assemblies between Hex-NARBr and Cy-NARCl as tetravalent XB acceptors, a divalent XB donor DIOFB, and small organic guest solvents (MeOH, MeCN and water). In the assemblies, both XB and HB

Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands

• Jennifer Klose,
• Tobias Severin,
• Peter Hahn,
• Alexander Jeremies,
• Jens Bergmann,
• Daniel Fuhrmann,
• Jan Griebel,
• Bernd Abel and
• Berthold Kersting

Beilstein J. Org. Chem. 2019, 15, 840–851, doi:10.3762/bjoc.15.81

• [Cd2L]2+ fragment. The switch from the trans to the cis form induces significant change of the π–π transitions of the supporting N6S2 macrocycle, which may be indicative of some increased π–π- (or charge transfer) interactions between the aromatic rings of the electron rich amino thiophenolato

Synthesis of the aglycon of scorzodihydrostilbenes B and D

• Katja Weimann and
• Manfred Braun

Beilstein J. Org. Chem. 2019, 15, 610–616, doi:10.3762/bjoc.15.56

• , partial hydrogenation of the aromatic rings had to be suppressed. Nevertheless, the aglycon 9 of scorzodihydrostilbenes B and D (2 and 4) was obtained in good yield from 8a. Hydrogenolysis of ketone 8b led to hydroquinone 10, however, along with a minor amount of mono-deprotected phenol 11. The main

Unexpected loss of stereoselectivity in glycosylation reactions during the synthesis of chondroitin sulfate oligosaccharides

• Teresa Mena-Barragán,
• José L. de Paz and
• Pedro M. Nieto

Beilstein J. Org. Chem. 2019, 15, 137–144, doi:10.3762/bjoc.15.14

• biosynthesis of this polymer. The presence of aromatic rings, such as the 4-methoxyphenyl group at the anomeric position, should be avoided because these groups can significantly modify the binding mode between the CS and the enzymes. For this reason, we introduced an isopropyl group in β-position of the

Adhesion, forces and the stability of interfaces

• Robin Guttmann,
• Johannes Hoja,
• Christoph Lechner,
• Reinhard J. Maurer and
• Alexander F. Sax

Beilstein J. Org. Chem. 2019, 15, 106–129, doi:10.3762/bjoc.15.12

Microfluidic light-driven synthesis of tetracyclic molecular architectures

• Javier Mateos,
• Nicholas Meneghini,
• Marcella Bonchio,
• Nadia Marino,
• Tommaso Carofiglio,
• Xavier Companyó and
• Luca Dell’Amico

Beilstein J. Org. Chem. 2018, 14, 2418–2424, doi:10.3762/bjoc.14.219

• (Figure 2). First, different substitutions on the 2-MBP scaffold were evaluated. Electron-donating substituents on both aromatic rings gave excellent results, furnishing the corresponding naphthochromenones 4b and 4c as single detectable diastereoisomers (>20:1 dr), with yields spanning from 53% to 83

A challenging redox neutral Cp*Co(III)-catalysed alkylation of acetanilides with 3-buten-2-one: synthesis and key insights into the mechanism through DFT calculations

• Andrew Kenny,
• Alba Pisarello,
• Arron Bird,
• Paula G. Chirila,
• Alex Hamilton and
• Christopher J. Whiteoak

Beilstein J. Org. Chem. 2018, 14, 2366–2374, doi:10.3762/bjoc.14.212

• , the acetanilide containing two aromatic moieties (1q) was subjected to the optimised reaction conditions (Scheme 4). The DFT studies suggested that selectivity should be observed between the two aromatic rings, in favour of the benzamide-type C–H functionalisation. In agreement with this proposal the

Synthesis and post-functionalization of alternate-linked-meta-para-[2ⁿ.1ⁿ]thiacyclophanes

• Wout De Leger,
• Koen Adriaensen,
• Koen Robeyns,
• Luc Van Meervelt,
• Joice Thomas,
• Björn Meijers,
• Mario Smet and
• Wim Dehaen

Beilstein J. Org. Chem. 2018, 14, 2190–2197, doi:10.3762/bjoc.14.192

• yield of 91%. The 3D structure of macrocycle 6 was confirmed by single crystal X-ray diffraction and shows approximate twofold rotational symmetry (point group C2, Figure 1). The dihedral angles between the aromatic rings are given in Table S2 (Supporting Information File 1, ring numbering as shown in

Calix[6]arene-based atropoisomeric pseudo[2]rotaxanes

• Carmine Gaeta,
• Carmen Talotta and
• Placido Neri

Beilstein J. Org. Chem. 2018, 14, 2112–2124, doi:10.3762/bjoc.14.186

• two respective proximal aromatic rings are oriented syn, as in the cone conformation. In contrast, a Δδ value of 0.3 or less is attributable to an anti-orientation between the phenol rings, as in alternate conformations. The de Mendoza’s “13C NMR single rule” [30][31], is focused on the 13C NMR

• ···O distance = 3.10 Å; average N–H···O angle = 157°). In addition, C–H···π interactions were detected among the methylene groups of the axle 2+ inside the calix cavity, and the aromatic rings of 1 [42], ( average C–H···πcentroid distance = 3.17 Å [42]; average C–H···πcentroid angle = 160° [43]). In

Revisiting ring-degenerate rearrangements of 1-substituted-4-imino-1,2,3-triazoles

• James T. Fletcher,
• Matthew D. Hanson,
• Joseph A. Christensen and
• Eric M. Villa

Beilstein J. Org. Chem. 2018, 14, 2098–2105, doi:10.3762/bjoc.14.184

• pairings of reactants. Crystals of 2cc’ suitable for XRD analysis were grown from slow evaporation of a methylene chloride solution. As shown in Figure 2, each of the three aromatic rings in this molecule’s fully conjugated π-system adopts a largely coplanar configuration. The dihedral angle between the 1

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• of substrates make this an ideal method for introducing nucleophilic ligands onto aromatic rings. Another publication from the Nicewicz group demonstrates the C–H direct cyanation of a variety of aromatic and heteroaromatic substrates. TMSCN is employed as the cyanide source, acridinium salts as the

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• macrocycles’ aromatic rings have been synthesized and used for the preparation of water-soluble triazolyl amphiphilic receptors with two or four polyammonium headgroups by CuAAC reaction with 3-bis[2-(tert-butoxycarbonylamino)ethyl]propargylamine. These macrocycles form stable aggregates in aqueous solutions

A pyridinium/anilinium [2]catenane that operates as an acid–base driven optical switch

• Sarah J. Vella and
• Stephen J. Loeb

Beilstein J. Org. Chem. 2018, 14, 1908–1916, doi:10.3762/bjoc.14.165

• ]rotaxane molecular shuttles outlined in Figure 1. This should be possible because of the structural similarities (size and shape) between the bis(pyridinium)ethane and benzylanilinium recognition sites. Each has a two-atom chain in a low energy, anti-conformation linking aromatic rings and the distance

A hemicryptophane with a triple-stranded helical structure

• Augustin Long,
• Olivier Perraud,
• Erwann Jeanneau,
• Christophe Aronica,
• Jean-Pierre Dutasta and
• Alexandre Martinez

Beilstein J. Org. Chem. 2018, 14, 1885–1889, doi:10.3762/bjoc.14.162

• helical arrangement of the linkers stabilized by intramolecular hydrogen bonds between amide and amine groups. The chirality of the cyclotriveratrylene unit controls the propeller arrangement of the three aromatic rings in the opposite part of the cage. 1H NMR studies suggest that this structure is

• the molecule (Figure 2). This also underlines how the chirality of the CTV unit propagates along the linkers to induce the propeller shape of the three aromatic rings in the south part of the hemicryptophane. This remote control of the helicity of the southern part by that of the northern CTV unit

Water-soluble SNS cationic palladium(II) complexes and their Suzuki–Miyaura cross-coupling reactions in aqueous medium

• Alphonse Fiebor,
• Richard Tia,
• Banothile C. E. Makhubela and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1859–1870, doi:10.3762/bjoc.14.160

• different substituents on the aromatic rings of the bromobenzene and phenylboronic acid. The results are summarised in Table 3 and the scope and yields compare favourably well with reported methods. First, the substrate scope of the phenylboronic acid coupling partner was investigated. Under the optimised

Host–guest complexes of conformationally flexible C-hexyl-2-bromoresorcinarene and aromatic N-oxides: solid-state, solution and computational studies

• Rakesh Puttreddy,
• Ngong Kodiah Beyeh,
• S. Maryamdokht Taimoory,
• Daniel Meister,
• John F. Trant and
• Kari Rissanen

Beilstein J. Org. Chem. 2018, 14, 1723–1733, doi:10.3762/bjoc.14.146

• , 1+BrC6 indicates either from combination of guest 1 and BrC6 or exo complex while 1@BrC6 denotes the endo complexation process. However, considering the host flexibility, ‘Δ’ (Table 1), which is the measure of difference between centroid-to-centroid distances of opposite host aromatic rings, guests

• cavity is represented as ‘h’, defined as the measured distance from the centroid of the lower-rim host carbon atoms to the nearest endo guest non-hydrogen atom. In the X-ray structure of 3@BrC6 (Figure 2a), guest 3, oriented parallel to the host aromatic rings (h = 3.43 Å) is positioned in one corner of

• the cavity with only the proton meta- to the N–O group interacting with a host aromatic ring. This short contact C–H···π(host) interaction is about 2.65–2.85 Å long. In 4@BrC6 (Figure 2b), once again guest 4 is oriented parallel to the host aromatic rings (h = 3.38 Å) and the H–G recognition occurs by

Synthesis of diamido-bridged bis-pillar[5]arenes and tris-pillar[5]arenes for construction of unique [1]rotaxanes and bis-[1]rotaxanes

• Ying Han,
• Li-Ming Xu,
• Cui-Yun Nie,
• Shuo Jiang,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2018, 14, 1660–1667, doi:10.3762/bjoc.14.142

• ], cyclodextrin [24][25][26], calixarene [27][28][29] and pillararene have been successfully employed as the wheel subcomponent. Pillararenes are new star macrocyclic compounds with aromatic rings para-bridged by methylene units and have unique tubular shape rather than cone [30][31][32]. In recent years, an

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• domino process for the introduction of both aromatic rings of diaryl-λ3-iodanes, though a small excess of this reagent is needed to obtain good yields. An initial N-arylation reaction of 3,5-dimethylpyrazole is performed in the presence of potassium carbonate, in xylene at 70 °C, releasing 1 equivalent

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

• Claudia Lar,
• Adrian Woiczechowski-Pop,
• Attila Bende,
• Ioana Georgeta Grosu,
• Natalia Miklášová,
• Elena Bogdan,
• Niculina Daniela Hădade,
• Anamaria Terec and
• Ion Grosu

Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115

• [32] revealed its selective absorption ability for N2 and CO2 in the solid state. The low complexation ability of cryptand 1 in solution for aromatic guests is due to the unfavorable conformation of the 1,3,5-triphenylbenzene central units in which the peripheral aromatic rings are twisted with

• and the host–guest interactions must be able to equilibrate the previously described ortho–ortho' hindrance and to bring the aromatic rings of the caps to coplanar conformations. In this work, we decided to investigate a new cryptand in which this steric hindrance is removed. Thus, we changed the

Synthesis of chiral 3-substituted 3-amino-2-oxindoles through enantioselective catalytic nucleophilic additions to isatin imines

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 1349–1369, doi:10.3762/bjoc.14.114

• 43 in good to high yields (78–99%) and uniformly excellent enantioselectivities (94–99% ee) regardless of the electronic character of the aromatic rings of the isatin and 1-naphthol and the position of their substituent (R1 and R2). Moreover, comparable excellent yields (90–97%) and

Selective carboxylation of reactive benzylic C–H bonds by a hypervalent iodine(III)/inorganic bromide oxidation system

• Toshifumi Dohi,
• Shohei Ueda,
• Kosuke Iwasaki,
• Yusuke Tsunoda,
• Koji Morimoto and
• Yasuyuki Kita

Beilstein J. Org. Chem. 2018, 14, 1087–1094, doi:10.3762/bjoc.14.94

• electrophilic aromatic rings, non-acidic carbonyl groups, and suitable oxygen, nitrogen, and sulfur functionalities. Carbonyloxy radicals derived from typical hypervalent iodine(III) carboxylates by photolysis and other conditions [65][66][67][68] are known to undergo irreversible decarboxylation [69][70

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• ) led to the corresponding chiral β-amino esters 71a–p with both high yields (77–99%) and enantioselectivities (79–94% ee). A range of both electron-donating and electron-withdrawing substituents at different positions of the two aromatic rings were compatible. Conclusion This review demonstrates that